It is generally known that during heating and burning of powdery raw materials, such as cement raw meal or the like, exhaust gases are produced in the gas suspension heat exchanger system which, depending upon the nature and origin of the raw materials contain a greater or lesser proportion of volatile pollutants, such as sulphur oxides, sulphur compounds and similar volatile compounds, which have been released during the heat treatment. Due to corresponding environmental protection requirements it is increasingly necessary to ensure that the emissions of the said pollutants in the exhaust gases from the heat exchanger are reduced. Efforts are therefore being made to develop appropriately or to extend the methods intended for heating and burning of the said raw materials (and the correspondingly designed apparatus and devices) with a view to reducing the said pollutant emissions in the exhaust gases from the heat exchanger.